1. Field of the Invention
The present invention relates, in general, to die and stamping presses and the like, and in particular, to apparatus for applying lubricant to such die and stamping presses during the stamping process.
2. Information Disclosure Statement
Die presses typically have a movable die that presses a workpiece, such as a piece of metal, between the movable die and a fixed die, so as to bend, shape, punch, stamp, and otherwise meld the metal into a finished product. So-called "progressive die" presses are well-known that sequentially perform such melding operations on workpieces. Die lubricant applicators have long been used for spraying lubricant from a pressurized source of lubricant through injector nozzles onto such die presses.
Heretofore, die lubricant applicators typically employed air-powered lubricant pumps to pump lubricant through one or more injector nozzles, and such pumps have been of the positive displacement type having reciprocating pistons driven by air pressure, as well as having check valves and springs, i.e., numerous moving parts. Such pumps are prone to failure, are unable to precisely control the application of lubricant, and require a source of air pressure to reciprocate the pistons of the pumps. Adjustment of such pumps usually requires manual turning of a screw or knob on the pump to change the stroke length of the reciprocating piston, thereby changing the lubricant volume brought into, and forced out of, the pump with each stroke of the piston. Such adjustments have the disadvantage that they cannot be performed remotely.
Additionally, prior art die lubricant applicators have the problem that there are tremendous impulses of lubricant pressure at the injector nozzles caused by the typically 9 to 1 pressure multiplication within their air-powered lubricant pump, causing the hydraulic pressure at the nozzle orifices to be multiplied by a factor of nine over the air pressure applied to the pump's piston by the air source. Such high pressure impulses at the nozzle orifices causes the lubricant to exit the nozzles at a terrific velocity and bounce (splash) when the lubricant strikes the dies and the workpiece, thereby wasting lubricant and splashing on the die press operator and the floor surrounding the die press, thereby creating a safety and environmental hazard.
Furthermore, as the workpiece moves sequentially through the die press to successive stations for bending, shaping, punching, stamping, etc., some lubricant is carried from earlier stations to later stations on the workpiece. It would be desirable to apply controlled and lesser amounts of lubricant to certain die press stations by occasionally skipping lubricant application cycles for one or more cycles of the die press.
It is therefore desirable to have an improved die lubricant applicator that precisely meters the application of die lubricant through injector nozzles and which substantially lacks the impulsive pressure spikes heretofore seen in applicator systems using air-powered lubricant pumps. Such an improved applicator should not require the use of air power at all, and should have a minimum of moving parts for increased reliability.
A preliminary patentability search in Class 72, subclasses 43 and 45, produced the following patents, some of which may be relevant to the present invention: Tetzloff et al., U.S. Pat. No. 3,561,238, issued Feb. 9, 1971; Rebsamen et al., U.S. Pat. No. 3,756,051, issued Sep. 4, 1973; Maddock, U.S. Pat. No. 3,877,271, issued Apr. 15, 1975; and Werner et al., U.S. Pat. No. 4,520,643, issued Jun. 4, 1985.
Additionally, the following other publications are known, all of which have publication dates more than one year prior to the filing of this application: Franklin Oil Corporation, F.A.S.T. Lube System (8 page brochure, date unknown); FlexSpray division of Metric Tool and Die Corporation, FlexSpray Expandable Airless Spray Stock Lubrication Systems (12 page brochure, date unknown); A-S Mfg. Inc., TeK-Spray. The Next Generation of Airless Spray Die Lubricant Application Systems (two page brochure, date unknown); and Pax Products, Inc., How to Spot a Quality In-Die Lubrication System, Metal Forming, Feb. 1993, at 9 (advertisement).
None of these patents or publications disclose or suggest the present invention.